Biotransformation of alpha-terpinene in common cutworm larvae (Spodoptera litura Fabricius)

alpha-Terpinene was mixed in an artificial diet at a concentration of 10 mg/g of diet, and the diet was fed to the last instar larvae of common cutworm, Spodoptera litura Fabricius. Metabolites were recovered from frass and analyzed spectroscopically. The alpha-terpinene was transformed mainly to 4-isopropyl-1,3-cyclohexadienoic acid and cumic acid. The allylic methyl group of alpha-terpinene was preferentially oxidized. The results indicate that the intestinal bacteria probably participated in the metabolism of alpha-terpinene. The aerobically active intestinal bacteria transformed alpha-terpinene to 4-isopropyl-1,3-cyclohexadienemethanol, and the anaerobically active intestinal bacteria transformed alpha-terpinene to p-cymene.